The present invention relates generally to medical testing, and more particularly to lateral flow assay.
In patient care, immunoassay technology provides simple and relatively quick means for determining the presence of analytes in a subject sample. Analytes are substances of interest or clinical significance that may be present in biological or non-biological fluids. The analytes can include antibodies, antigens, drugs, or hormones.
The analyte of interest is generally detected by reaction with a capture agent, which yields a resultant or complex that is more easily detected and measured than the original analyte. Detection methods can include a change in absorbance, particularly a change in color, change in fluorescence, change in luminescence, change in electrical potential at a surface, change in other optical properties, or any other easily measured physical property indicating the presence or absence of an analyte in a sample.
New immunoassay devices have been developed that play an important role in areas such as clinical chemistry. They are used by skilled clinicians and laypersons alike. Thus, there is a strong impetus to provide devices that are simple and reliable. Desirably, the assays are single-step tests wherein the user need only apply the sample prior to viewing the result. Single-step tests obviate the necessity of performing complicated and time consuming processing steps that may introduce errors in the end result.
Immunoassay tests are often critical to patient care. Assays are routinely performed to detect the presence of particular analytes that are present when a human or non-human subject has a particular disease or condition, such as HIV, flu, alcohol, drugs, ovulation, pregnancy, etc.
Immunoassay technology now allows for assay tests to be performed without the complex and expensive equipment used in hospitals and laboratory settings. Kits for performing assays are now available for home or point of care use to quickly determine the presence of a disease or condition by providing qualitative results for the analyte or tested condition. These kits generally include strips that provide a visual indication when the analyte being sought is detected.
Generally, these assays have an extended base layer on which a differentiation can be made between a sample application region and an evaluation region. In typical use, the sample is applied to the sample application region, flows along a liquid transport path, which runs parallel to the base layer, and then flows into the evaluation region. A capture reagent is present in the evaluation region, and the captured analyte can be detected by a variety of protocols to detect visible moieties as described above associated with the captured analyte.
The above assays are called lateral flow assays or immunoassays and are currently single use and disposable.